Add support to create mapping table in Developer

[royendo]

Is your feature request related to a problem? Please describe. I want to create access policies in Developer but i cannot create a table in DuckDB/CH directly. I would be required to start a client in CLI and create table using SQL then manually adding rows based on XYZ

Describe the solution you'd like If there was a way to create a table in DuckDB so that I can create a mapping table to create dashboard access

Describe alternatives you've considered Can create the source external to Rill, [any of our other connectors] but for users who are using upload_csv, etc. and dont have access to some source

Additional context